Piston ring



y 30, 1933- F. w. WILKENING 1,911,735

PISTON RING Filed Oct. 25, 1930 2 Sheets-Sheet 1 A TTORNEY.

y 1933- F. w. WILKENING 1,911,735

' ING PISTON R Filed Oct. 25, 1950 2 Sheets-Sheet 2 INVENTOR.

Patented May 30, 1933 UNITED STATES PATENT, OFFICE- FREDERICK W. WILKENING, F PHILADELPHIA, PENNSYLVANIA, ASSIGNOR ".IJO WILKENING MANUFACTURING COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A

CORPORATION OF DELAWARE PISTON RING Application filed October 25, 1930. Serial No. 491,157.

The present invention relates generally to a class of piston rings commonly referred to as oil-control rings, and it relates more particularly to a novel oil-control ring construction, and the method of making the same, whereby certain deficiencies and undesirable characteristics of the prior oil-control rings, flowing both from their inherent structure and from the method by which they were made, may be entirely eliminated, and whereby a much improved product may be obtained.

Among the several practices followed heretofore when making oil-control rings, it has been the practice of providing elongated slots extending radially through the ring. By this practice, the cross-section of the ring contained alternate weak and strong sections of comparatively great extent, because whereever the elongated slots were, the general cross-section of the ring over that area was reduced to about two-thirds of the original cross-section. Due to this, the outward radial tension set into the ring, would not produce a uniform outward radial force at' all points, but produced points of greater and lesser pressure between the ring and the cylinder.

Thus, even though a slotted oil-control ring, as built heretofore, was light tight throughout with respect to the cylinder, yet the outward radial force of pressure exerted by the ring upon the cylinder variedbetween alternate high and low points, corresponding to the slotted and non-slotted portions of the ring.

To overcome these undesirable characteristics inherent in the prior slotted oil-control ring structures, flowing partly from the method by which they are ma de,-my present invention contemplates a certain radially perforated and externally double channeled ring and a certainprocess or method ofmaking said rings, whereby "a substantially uniform "outward radial pressure may be obtained between'rin'gand cylinder under all conditions, and whereby'the desired o'il drainage through the radialperforations of the'fjring may be maintained notwithstanding a substantial reduction in the aggregate cross-sectional" area of such perforations, and whereby a maximum uniformity of resultant product may be obtained.

With the foregoing and other objects in view, my invention consists of and includes certain method steps and certain features of construction which will appear more fully from the following detailed description.

For the purpose of illustrating my invention I have shown in the accompanying drawings one form thereof which is at present preferred by me, since the same has been found in practice to give satisfaction and reliable results, although it is to be understood that the various instrumentalities of which my invention consists can be variously arranged and organized and that my invention is not limited to the precise arrangement and organization of the instrumentalities as herein shown and described.

Referring to the drawings in which like reference characters represent like reference the cylinder walls, shown on a much enlarged scale. A

Figure 5 represents. afragmentary sectional view on line 55 of Figure 4;. 7

In carrying out my invention, I first cast the piston rings individually, from asuitable grade of ,castiron, said rings beingcast su'fiicien'tl'y oversize and slightly out-of-round :or elliptical so that upon the subsequent removal 1 of a small section ofthe ring the ring can be collapsed linto ,a true circular shape with its ends "abutting, and of the, desired diameter against the tension inherent in the body of the ring'.fi .t" v

' Thereafter, the rings are. ground or turned on "their. two plane parallel faces, until such-1 faces are aneaana the" desired thickness of ring obtained. A suitable section of the ring is then removed, so that the ring might be collapsed to the desired diameter. This may be done by any suitable sawing or milling operation. The rings are then collapsed and retained in the collapsed condition by any suitable means ;and while in said condition the rings-are turned externally and also preferably internally as well, to the desired diameter.

Thereafter, an outer double channel 12 is turned into the ring 11, while the ring is in the collapsed condition ;said double channel 12 including an outer substantially rectangular portion 13 and an inner portion 14 of semi-circular or other curved cross-section, the diameter or maximum width of which is less than the width of the rectangular ortion 14 of said double channel 12; therey providing an outer rectangular channel and an inner circular channel.

This double channel is preferably turned into the ring 11 equidistantly from the two plane parallel faces 15 and 16 thereof, so as to provide a pair of outer annular bearing surfaces 17 and 18 respectively, on the outer periphery of the ring, of equal width. The axial width of the outer rectangular channel 13 is so proportioned with respect to the width of the ring, that it will occupy ap roximately one-half, more or less, of the wi th of the ring, thereby providing annular bearing surfaces 17 and 18, each approximately one-quarter, more or less, of the width of the ring.

Thereafter, a series of generally radial apertures 19 are drilled through the ring from the inner circular channel 14 to the inner diameter 20 of the ring. The radial apertures 19 may be of any suitable number and are preferably equidistantly spaced with respect to each other, and are preferably of a diameter slightly greater than the width of the inner channel 14 and slightly less than the width of the outer channel 13. The drilling of these radial apertures 19 may be effected while the ring is either in the collapsed or expanded condition ;the inner channel 14 acting, inter alia, as a guide for centering the apertures with respect to the outer channel 13, and hence with respect to the ring as a whole.

Thereafter, the ring is installed in the ring groove 21 of the piston 22 in a manner shown in Figures 2, 4 and 5; the ring being ultimately collapsed to the diameter of the cylinder wall 23.

A series of drain apertures 24 are preferably provided from the bottom of the ring groove 21, through the piston wall, for the purpose of draining the oil from the said groove, as indicated particularly -in Figure 4.

If desired, to augment or replace the outward radial pressure inherent in the body of the ring, a flat steel spring ribbon expander 25, may be provided, being suitably corru- 3 and 4. The radial expander spring 25 is I interposed between the bottom of the ring groove 21 and the inner diameter of the ring.

One of the advantages of my present novel ring construction is that the tension inherent in the ring is not broken-or interrupted materially by ring portions of substantial length having reduced cross-sectional areas and that the outward radial pressure of the ring, with respect to the cylinder may be maintained substantially uniform throughout the circumference of the ring and at the same time a true circular and perforated ring may be obtained.

By reason also of the inner channel 14', the aggregate cross-sectional area of the perforations through the ring may be much reduced without interfering with the desired oil drainage through the ring, because said inner channel 14 tends more effectively to guide the oil film to the radial apertures 19.

The action of the ring is as follows The comparatively narrow annular'contact surfaces 17 and 18 of the ring, being urged into contact with the cylinder wall by a uniform pressure inherent in the entire ring, the pressure per unit of contact area is increased so. that the comparatively narrow and opposed annular contact surfaces 17 and 18 tend to break through the film of oil adhering to the cylinder surface and to ride back and forth over a comparatively thinner oil film than what would obtain were the contact surface of the ring equal to the entire width of the ring. This causes some of the oil film to be scraped onto the side walls of the outer channel 13, during the successive strokes of the piston. The oil film thus gathered on the walls of the outer channel 13 then passes onto the circular wall of the inner channel 14, from whence it is effectively drained through the comparatively small radial apertures 19. The oil is thus gathered behind the ring and is then drained back into the crank case through the drain apertures 24 extending form of my novel ring construction, the ring may be caused to follow any Slight irregularities in the cylinder wall, by reason of its somewhat pliant and lifeless condition and by reason of the uniformly distributed outward radial pressure exerted upon the ring by the expander spring 25 hearing against it at a series of uniformly spaced points.

In this form of my present invention, the comparatively narrow bearing surfaces 17 and 18 may be urged into contact with the cylinder walls with substantially uniform pressure of suflicient degree to cause an eificient gathering of the oil into the channel 13 and a drainage of the oil from the walls of said channel and from the walls of the inner channel 14 through the small radial-openings 19.

I am aware that my invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate'the scope of the invention.

Having thus described my invention, what, I hereby claim as new and desire to secureby Letters Patent, is

1. In combination with a cylinder and a annular channel having a pair of plane and I parallel outermost side-walls and an inner wall portion of curved cross-section intermediate said outermost and parallel sidenular channel through said ring, and a series of holes extending from the bottom of the ring groove through the wall of the piston, and means intermediate the inner wall of the ring-receiving groove and the piston ring for exerting a generally uniformly distributed outward radial pressure upon said ring whereby the two annular cylindrical contact surfaces of the piston ring are urged into contact with the cylinder wall and are caused to follow any slight irregularities of the same. Y a

In testimony whereof I have hereunto set my hand this 26th day of September, 1930.

FREDERICK W. WILKENING.

piston adapted for reciprocation therein and having an annular, parallel walled ring receiving groove, of a split metallic piston ring operatively disposed within said ring receiving groove, said piston ring having a pair of spaced parallel outer cylindrical surfaces for contacting engagement with the cyl 4 inder walland having an annular channel intermediate said pair of outer contact faces, said annular channel having a pair of plane and parallel outermost side-walls and an inner wall portion of curved cross-section intermediate said outermost and parallel sidewalls and spaced from said side-walls by corresponding connecting wall portions intermediate said plane parallel outermost sidewalls and said inner wall of curved cross- 7 1 groove through the wall of the piston.

2. In combination with a cylinder and a piston adapted for reciprocation therein and having an annular, parallel walled ring receiving groove, of a split metallic piston ring operatively disposed within said ring receivmg groove, said piston ring having a pair of spaced parallel outer cylindrical surfaces for contacting engagement with the cylinder wall and having an annular channel intermediate said pair of outer contact faces, said 

